I ran out of things to do while quarantined...and look what I found. An almost complete Reatta Portfolio (what you see is what you will get). I think this may have been the portfolio of the third (or fourth) Reatta I bought many years ago.
Forum price is $219.00 + $15.05 shipping (within the continental US). Send a PM if interested.

I was dusting off some boxes and found (I think) two complete 1990 zippered portfolios (pen, flashlight, tire pressure gauge and lots of documentations including a letter to the buyer). Both have 95% the same items. But one has a full color apparel order form from Buick and the plastic/leather key holder, the other does not (and its missing the pen). One also has a letter written to the buyer from Buick and the other does not. I had read that through the 1990 MY, in mid-cycle the portfolios differed. Has anyone composed a list of exactly which items came inside a portfolio? I did a forum search going back to 2010 and couldn't find a posting that had an itemized list. Thanks.

I wasn't aware Marck has the FB page shut down for public viewing (that's unfortunate).
IMO, older folks (unlike yourself Ronnie - you're classified as 'historic' ) liked to tinker mechanically with cars. Its the DYI mentality. It's part of the make-up of that generation. And that still applies as your generation is mostly retired. Younger folks (sub 40ish), have a 'disposable' mentality. No need to know how to fix something. Either have someone else do it (often due to long work hours and family time obligations), or 'dispose' of the problem and get something else.
FB is like Windows 10. Its but a shell for what once was. FB replaced the classic BBS' of the 1980s/early 1990s just as Windows is a shell for DOS. Your generation looks for the 'how do I do this/How does this work. Whiles sub 40s, who work long hours, has two kids, leases two cars, has a mortgage and $10K in rolling credit card debt,...don't care for the details of how things work.
It would be nice to hear Marck's opinion. My guess his is client base averages 65+ years and business isn't as strong as it could be (only because that generation is dying off). IMO, if he doesn't branch off into the Mustang, Camaro, Corvette, Mopar world, he won't have a sustainable business model in a few years.

Getting back to Barney's original post, from a consumer's perspective, my experience having sold 13 Reattas is...no.
About 10 of the cars sold to people who had discretionary funds and was looking for a car from their youth they would drive on weekends. Some were looking at Mustangs, Camaros, Allantes, Chryslers. They were not looking specifically for a Reatta - just a car to recapture memories. Their ages ranged from 50-70ish.
One car sold to a gentleman who was an 88 year old retired Air Force colonel. He bought the car to drive for a month or two with the intention of giving it to his grandson. He was looking for an Allante or Corvette but found my listing on CL. The other two cars (which were coupes) were purchased from blue collar guys looking for a weekend car. Both these cars were in better then average condition. But far from the condition the other 11 were in.
Not one bought the car assuming it was/would be a collectible and nobody specifically sought after the Reatta. This (and the previous) generation collects sneakers - not cars.
As for the forum diminishing, it's generational. Most of those who don't wear Depends that have a Reatta have migrated to Facebook. But I think as a whole, the collector car hobby took a big hit from the 2008 recession and has not recovered.

Mostly disagree with the above two posts. I've owned two 1990 silver/gray convertibles (one I still own with 50K miles). The other had 52K miles when I sold it. Both are two of only 60 verts made in that color combo. Doesn't make a different on resale value or collectability. Reattas are nice boulevard cruisers for a weekend drive. But they are not collectible and I don't see their value increasing much (nor do I see value decreasing much). And being realistic, the old farts (and I'm still a few years from being in that category) with discretionary funds who spend $12K for a car, power to them. But they're a (eventually) dying breed. Its the 40 and under folks the car (or most collectible cars) needs to attract. And that's not happening. World has changed. Even teenagers/20-somethings (the next generation) don't care about cars - they care about technology and saving the world from climate change Even cars shows have shown a steady decline in participation the last 10-15 years.
On a side note, there were some in this forum who said once the Reatta would reach 25 years, it would be an instant collectible and value would gradually increase. Carnak could have predicted that wasn't going to happen.

Regarding the black '89 above, FWIW I spoke to the owner 2-3 weeks ago.
It's a one owner car with one re-paint (owner said re-paint looks good but not great). Interior was done about 2 years ago. Car needs tires, probably struts/shocks all around. I couldn't get a clear answer regarding the ABS. Car was mostly her husband's car until he fell ill, He no longer drives and the car sits in a garage.
IMO, if you like the color combo and can get it for a few hundred dollars less, expect to invest $2,000 (tires and shocks), flush/replace fluids and you'll have a nice, rust free low mileage SoCal car.

https://www.ebay.com/itm/1990-Buick-Reatta-Convertible/163194236607?hash=item25ff226ebf:g:ltkAAOSwkXRbbFkq
Take a look if interested in a red/gray convertible. One owner, 51,300 miles, looks good (don't know about condition of top). Do your homework but at an asking of $8,700, looks like a bargain. It's in a place called Nebraska (I think they are part of the union).